Is Inkscape the only graphics program that can be used, since it's a SVG file?
I've not used it, but then I've hardly used others as well.

You may do that but inkscape is really very easy and layer is only a onion skin concept.
the circle you wanting to enlarge or change is on layer 2. Layer has 2 button aside, one is an eye which make layer visibility on or off and 2nd is lock which locks the content not for further editing and if the layer 2 i have send is locked first unlock it and click on the circle element as its highlighted it will show handles and for very basic concept there is a help page which are svg files in the inkscape last menu button.
after you finish click on export button in file menu and select canvas area as png file and path where you want to store it

G.Traductor:
Nice images to place wallpapers. It's a shame that to lower them you are forced to have a Yahoo account that is not to my liking.

Thanks and you dont need a yahoo account, simply download largest resolution and open it in gimp which is preinstalled in MX, Select crop tool and select area you want and click on export as, and in file extention manually enter .jpg if you want it in JPEG format or .png if in PNG format.
For making file small, please go to image tab and select size and enter your desired resolution and aspect ratio.
Anther method for image distribution is installing a plug in called save for web, available in repository, and it will drastically make image size smaller for use in awebsite or mail or in a document,

I tried using Inkscape for the first time and got a more stretched (ie, longer) oval shape than yours, but couldn't make the curved "C" bracket on the left of the oval follow its shape properly. I'll post my first attempt here later tonight.

But I couldn't figure out how to curve the "C" on the left to follow the outline of the oval. Also, my preference is a "capsule" shape, ie, a rectangle with rounded ends, but I have no idea how to achieve that.

But I couldn't figure out how to curve the "C" on the left to follow the outline of the oval. Also, my preference is a "capsule" shape, ie, a rectangle with rounded ends, but I have no idea how to achieve that.

First Congrats for your 1st try on inkscape. Once you start using, you will find how easy and logical the software is.
For 1st time user i recommend to go in Help tab and click tutorials, They are really a good point to start.

Now for the problem you mention, i will try to upload an file latter, but for help and your self doing this may help:-
The Curve c is in layer 1 and it was made by making an triangle and then intersect with the left circle making an enlage version of it, so that aspect ratio and width and gap are maintained.
For right circle which you want a rounded rectangle, you may try to place one rectangle shape from left toolbox(F4), and click on edit nodes(F2), then drag the handle to make edges rounded.

But I couldn't figure out how to curve the "C" on the left to follow the outline of the oval. Also, my preference is a "capsule" shape, ie, a rectangle with rounded ends, but I have no idea how to achieve that.

First Congrats for your 1st try on inkscape. Once you start using, you will find how easy and logical the software is.
For 1st time user i recommend to go in Help tab and click tutorials, They are really a good point to start.

Now for the problem you mention, i will try to upload an file latter, but for help and your self doing this may help:-
The Curve c is in layer 1 and it was made by making an triangle and then intersect with the left circle making an enlage version of it, so that aspect ratio and width and gap are maintained.
For right circle which you want a rounded rectangle, you may try to place one rectangle shape from left toolbox(F4), and click on edit nodes(F2), then drag the handle to make edges rounded.

Thanks

Thanks for the tips.

However, by curved "C", I mean the light brown outline to the immediate left of the oval shape. See red arrow in the pic below. It's part of the same layer as the oval. I clicked on the "C" and tried to stretch, tweak and pull it, but just couldn't get it to follow exactly the curvature of the oval. Would appreciate some guidance on this.

Also, my intention is to completely replace the brown oval with a capsule shape, if possible. But if not, I can make do with the oval if the curved C issue can be solved. This is after all for my own use. :-)